GOALI: Transforming Wavefronts with Additive Manufactured Electromagnetic Metasurfaces

Regents Of The University Of Michigan - Ann Arbor, Ann Arbor MI

Investigators

Abstract

Part 1 A new approach to controlling electromagnetic waves is proposed using finely textured surfaces (metasurfaces) fabricated through advanced additive manufacturing. Unlike conventional curved lenses that simply phase correct and focus waves, the proposed metasurfaces can transform both the phase and amplitude of electromagnetic waves. Today, such functionality requires complex assemblies of lenses (compound lenses) that are often bulky and cost prohibitive. The advance-manufactured metasurfaces promise to extend functionality, reduce size and weight, as well as lower manufacturing costs over these existing lens-based solutions. The proposed, finely-textured surfaces (metasurfaces) will enable ultra-thin, low cost and highly efficient antennas for airborne satellite communications and imaging, as well as make possible low-cost, low-power imaging and radar solutions with applications to environmental remote sensing, autonomous vehicle navigation and security scanners. The proposed metasurfaces promise to separate electromagnetic functionality from shape. Conventional lenses derive their electromagnetic properties from their shape. The proposed surfaces can take on arbitrary shapes while performing a targeted functionality, since they derive their properties from their fine texture. This will enable them to be seamlessly integrated into various form factors. This collaborative University-Industry effort supports advanced manufacturing in America. Specifically, the proposed research will advance additive manufacturing methods through the development of affordable, advanced-manufactured electromagnetic devices. An integral component of this project is education and outreach. It includes internships for graduate students with the industry partner, summer undergraduate research projects at the University of Michigan, as well as the development of a short course and graduate course material in electromagnetic metamaterials and additive manufacturing by the University PI and Industry co-PI. The outreach effort will also include the organization of joint technical sessions at prominent conferences with both academic and industrial invitees. Part 2 The objective of this University-Industry research effort is to develop reflectionless metasurfaces capable of transforming an impinging electromagnetic wavefront, in both phase and amplitude, to a desired aperture field. Unlike conventional, curved lenses that simply phase correct wavefronts, the proposed metasurfaces can apply extreme phase, polarization, and amplitude changes to a wavefront in a low-loss manner. Additive manufacturing capabilities of the industry partner will be advanced, and exploited to realize the proposed metasurfaces that require both in-plane and out-of-plane structure. Unlike the metasurfaces reported to date that offer only polarization and phase control, the proposed metasurfaces will also be able to manipulate the amplitude distribution of a wavefront. A theoretical framework and systematic approach to designing such metasurfaces is proposed. The metasurfaces will possess both tangential and normal (out-of-plane) surface parameters that can be electric, magnetic, and magneto-electric. The complex geometries required to achieve these surface parameters will be fabricated through advanced additive manufacturing methods developed by industry partner. The additive manufacturing methods allow both low-loss dielectrics and high conductivity metals to be seamlessly combined into three-dimensional geometries. Controlling the polarization, phase and amplitude of electromagnetic waves is critical to electromagnetic systems ranging from RF to optical wavelengths. The proposed metasurfaces will enable ultra-thin microwave, millimeter-wave and sub-millimeter-wave lenses that can generate wavefronts with arbitrary amplitude, polarization, and phase profiles. Applications will range from optimal antenna-feed coupling, lenses that allow precise control over the radiated beam pointing direction and sidelobe level, to the formation of perfect holograms with images reconstructed in both phase and amplitude. Several business units of the industry partner will benefit from the extended functionality, reduced size and weight, and potentially lower manufacturing cost of these metasurfaces that are enabled by additive manufacturing. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.